1. Field of Invention
The present invention relates generally to surgical instruments, and more particularly, to a high intensity ablation device to create linear lesions in tissue, such as a surface of the heart.
2. Description of Related Art
Atrial fibrillation (AF) is a commonly occurring disorder that causes the atria to beat erratically. This condition can cause thromobogenesis and strokes. It can be treated pharmacologically, but many patients are not responsive to these therapies. It is generally accepted that creating lesions in the atria that create conduction blocks are a good way to do this.
There have been a number of procedures developed to treat atrial fibrillation. These include the surgical MAZE procedure, where the heart of the patient is stopped and the left and right atria are opened. The atrium is then divided into pieces and sewn back together. It is presumed that the scars that form from these cuts effectively block electrical conduction in the atria. This technique suffers from all of the morbidities associated with placing the patient on cardiopulmonary bypass and stopping the heart. Further, it is a time consuming and technically difficult procedure to perform.
There are also a number of catheter based interventional techniques that use RF energy or cooling to ablate the tissue and form scarring. These require mapping of the aberrant foci within the atria, and then the selective ablation of the foci. This too is a time consuming and difficult procedure. Ablation catheters are commercially available for this procedure. More recent work suggests that a large majority of patients (perhaps as high as 80%) will have their atrial fibrillation eliminated by ablating circumferentially around the pulmonary veins. A catheter is commercially available that can be inserted percutaneously into the pulmonary veins and used to ablate the tissue in the veins. The drawback to this technique is that ablating circumferentially within the veins may cause pulmonary vein stenosis. It also seems likely that a more complicated lesion set is required to be effective in the majority of patients. It is desirable to have tools and techniques that will allow these lesions to be easily created on the myocardial tissue rather than the venous wall.